Rod Taylor wrote:
> Restarting slon for node 1 will clear all of the connections (takes some
> time as a result of the now very heavy contention over pg_listener).
>
That's *very* interesting.
Two thoughts:
1. You might consider shutting off the node 1 slon altogether, and
running generate_sync_event() once in a while from cron.
Note that this has been in Slony-I since about 1.0.5...
create or replace function @[EMAIL PROTECTED](interval)
returns int4
as '
declare
p_interval alias for $1;
v_node_row record;
BEGIN
select 1 into v_node_row from @[EMAIL PROTECTED]
where ev_type = ''SYNC'' and ev_origin =
@[EMAIL PROTECTED](''@NAMESPACE@'')
and ev_timestamp > now() - p_interval limit 1;
if not found then
-- If there has been no SYNC in the last interval, then push one
perform @[EMAIL PROTECTED](''@NAMESPACE@'', ''SYNC'', NULL);
return 1;
else
return 0;
end if;
end;
' language plpgsql;
The original intent was to have this in a crontab, and run it with
interval '5 minutes' so that if the origin node's slon falls over,
there's still a periodic SYNC. If the slon is running, then you're
getting SYNCs more often than every 5 minutes, so this would do NOTHING.
2. Significantly increase the sync_interval parameters
The default is to generate a SYNC (and attendant pg_listener churn) once
per second.
If you've got a subscriber that won't be processing SYNCs until 20h from
now, there's little point in generating 3600 SYNCs per hour.
Bump up sync_interval and sync_interval_timeout to, say, 60000, and
there will be just 1 SYNC (and killed-off pg_listener entries) once per
minute. You should still have "bite-sized" SYNCs; you're still getting
60/h.
Those strike me as changes that could be made in 1.1.5 (and earlier)
that would alleviate the problem.
> That's why I expect it to go away after Slony 1.2 is release -- no more
> pg_listener entries)
Yeah.
Happily, I haven't seen anything in this thread that points at there
being big things that need to be changed that *aren't* already in CVS
HEAD. All of the issues appear to be resolved by changes that have been
made.
Next step, 1.2...
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